According to the Met;
There was a fourfold increase in burglaries in the resort peaking in April 2007. Two of the burglaries in April were in Block 5 where Madeleine disappeared from. In both these burglaries entry was via a window. In the first burglary the British occupants had just arrived on 16 April when a man called at the door asking for the "German family". He is described as white, aged in his 20s, fair/blond hair, short in length. They discovered the burglary after they returned from dinner.
http://web.archive.org/web/20150302140142/http://content.met.police.uk/Appeal/Madeleine-McCann-Appeal--October-2013/1400020463601/1257246745782According to the bookkeeper;
on 16th April 2007 there was a theft from an apartment in Block 5 L, from where a plasma display screen, credit cards and a mobile phone belonging to the respective guests were taken.
As far as she knows, as she prepared the papers for the insurance company, the theft took place at the end of the day and according to the guests the event happened when they had left for dinner after completing check in and having left their suitcases in the apartment.
She says that she does not remember having been told that doors or windows had been forced, the guests having said that they had just left the door on the latch, however she is not certain.
http://www.mccannpjfiles.co.uk/PJ/MARIA-GONCALVES.htmAs with everything in this case there are questions arising.
Did the Portuguese police tell the Met there was a four fold increase in burglaries?
Did the Portuguese police tell the Met entry took place via a window? If so there would have been evidence of that.
Were the Portuguese police called? MG doesn't mention if they were, but an incident number would have been needed to claim from a UK travel insurance company.
If the claim was with a Mark Warner scheme I would expect the fact that credit cards were left in the apartment to be questioned, as the advice was to lock valuable items in the safe at reception. Also not locking the door.